Induction coupled plasma devices have been employed for generating a high temperature plasma into which a sample solution to be analyzed is introduced for dissociation, atomization and ionization. The resulting material may be analyzed using a mass spectrometer or an optical measuring apparatus such as an atomic absorption spectrophotometer or an emission spectrophotometer. Detection limit values of optical measuring apparatus are in the sub-PPB level while detection limit values of mass spectrometers may be in the PPT level.